Jibs



June 3, 1955 P. F. MOSKOPF ETAL JIBS 2 Sheets-Sheet 1 Filed Jan. 11, 1963 June 1965 P. F. MOSKOPF ETAL 3,

JIBS

2 Sheets-Sheet 2 Filed Jan. 11, 1963 United States Patent 3,187,905 JIBS Peter Franziskus Moskopf, Heinrich Boden, and Heinrich Valentin Mengden, all of 21 Hermannstrasse, Neuwied (Rhine), Germany Filed Jan. 11, 1963, Ser. No. 250,837 4 Claims. (Cl. 212-55) This invention relates to jibs. A large number of diiferent kinds of jibs for mounting on mechanical handling vehicles is already known. Such jibs are used either at one location to move loads from one position to another or to remove loads from a stockpile, deposit them on the handling vehicle and then to unload them at some other place to which they have been conveyed on the vehicle. The present invention is applicable particularly, but not exclusively, to jibs of the latter kind for handling heavy loads. When a jib of the aforementioned kind is pivoted to the handling vehicle at a position which tendsto cause the vehicle to tip when the jib is used, the difliculty has arisen, particularly when heavy loads are handled, of utilizing the loading platform of the vehicle to an optimum extent without providing counter-balancing weights. If the tilting moments are to be taken up completely by the vehicle it is naturally best to make use of the weight of the vehicle itself, and particularly of the weight of the motor, in order to provide the required counterbalancing moments. It has thus been proposed to mount the jib directly behind the drivers seat, that is to say as close as possible behind the motor of the handling vehicle, in order to make best use of the weight of the motor as a counterbalancing Weight.

Another difficulty which has arisen in the handling of heavy loads is that the loading platform can rarely be efliciently used because the range of action of the jib is 1 too limited. The heavy loads may be, for instance, freshly made precast concrete parts such as are usually stacked on boards While still wet in order to dry. Such precast concrete parts may be lifted and 'put down layerwise. Particular difiiculty arises when space is restricted and the handling vehicle can only approach the stack endwise.

It is an object of the present invention to provide a jib which can, if desired, be pivoted near to the motor of a handling vehicle, and be constructed to extend for a substantial distance while being capable of efiiciently serving the loading platform of a handling vehicle.

The present invention provides a jib comprising a main arm and an extension arm carried by and axially extendible from the main arm. If desired, more than one extension member may be provided.

Preferably, at least the main arm is of substantially rectangular cross-section. It is also preferred that the extension arm is telescopically arranged within the main arm.

In a preferred form of construction, the underside of the main arm is slotted or open for the reception of a loading device attached to the end of the extension arm so that the loading device can be retracted beyond the end of the main arm.

It is also preferred that at least the portion of the main arm which has a slotted or open underside is of substantially inverted U-section and the extension arm is of closed rectangular crosssection.

The manner in which the extension arm is supported is of particular importance when heavy loads are to be handled. Preferably the main arm should have at least two guideways in its interior for sliding blocks, rollers, wheels or like members from which the extension arm is suspended. Generally speaking it is not sufficient to extending to a height of, for example, 4 metres.

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provide a single guideway for the relative displacement of the extension arm in the main arm of the jib.

For extending and retracting the extension arm or arms, any suitable actuating means may be provided. However, it is preferred to use ram cylinders which are advantageously disposed inside the main arm or-if several extension arms are provided-inside the extension arm below that which the ram cylinders operate.

Since the extendibility of the jib is desirably the maximum possible, it has been found useful to provide two oppositely-acting ram cylinders for the relative displacement of the extension arm and the main arm, located side by side in a vertical or any other convenient plane. A considerable length of extension and contraction can thus be achieved.

When the jib is pivotally mounted on a mechanical handling vehicle, the pivot should be located as far forward as possible (viewed in the direction of travel) in order to minimize the tendency to tilt. It is also readily possible to mount a supporting arm or a pedestal of the jib on a ring gear to permit the jib to be horizontally slewed in conventional manner.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which FIGURE 1 is a schematic side elevation of a mechanical handling vehicle having a jib according to the invention,

FIGURE 2 is a longitudinal section of the jib with the extension arm retracted,

FIGURE 3 is a longitudinal section of the jib with the extension arm partly extended,

FIGURE 4 is a section taken on the line 44 of FIG- URE 3, and

FIGURE 5 is a similar section to that shown in FIG- URE 4 of an alternative form of construction.

The mechanical handling vehicle 1 is generally of conventional construction and comprises a rigid supporting pedestal 2 adjacent the drivers seat. In the usual manner the motor may be mounted in front of or alongside the drivers seat. The supporting pedestal 2 is located sufficiently far forward for the weight of the vehicle to balance any tilting moments which may arise when a load is being carried by the jib.

The supporting pedestal has a bifurcated top connected by a transverse pivot pin 3. Pivotally mounted on this pin is the main arm 4 of the jib. The main arm contains a telescopically extendible extension member 9. The main arm has a rectangular inverted U-shaped cross section and the extension member has a closed rectangular cross-section, as Will be readily seen by reference to FIG- URE 4 or S. Secured to the sides of the main arm 4 are flanges 5 fitted with pins 6 upon which the ends of the piston rods of ram cylinders 7 are pivotally mounted. The ram cylinders 7 should be such that the jib can be held at any desired inclination. Behind the vehicle, FIG- URE 1 shows a stack 8 of prefabricated concrete parts, The handling vehicle 1 can be backed up to this stack in such manner that the jib can be set to work as indicated in FIGURE 1 to remove the concrete parts from the stack one by one and place them on the vehicle. Slidably located in the main arm 4 of the jib is an extension arm 9 which, at its free or outermost end, has a carrier arm 10 from which is suspended gripping means 11 for gripping and handling the heavy concrete parts. The stack concrete parts can be lifted oif individually from different levels as indicated in broken lines, deposited on the hantiling vehicle and then re-stacked elsewhere at different leve s.

The pedestal 2 may be rotated horizontally and to this end a ring gear is conveniently provided between the pedestal and the body of the vehicle. Similar ring gears are used for instance in slewing cranes.

The main jib arm 4 has an open or slotted underside at least to the point where the carrier arm is shown located in FIGURE 2. The main jib arm may be con-. structed for instance of welded sheet metal parts. In its interior, it is provided with guideways 12 formed by inwardly projecting ledges 13. These ledges support rollers or wheels 14 attached to the extension arm 9. The extension arm 9 is thus movably supported on pairs of rollers 14 inside the main arm of the jib. The extension illustrated in FIGURE 4 contains a carriage 15 for two ram cylinders 16 and 17. Mounted on the top of the carriage 15 at one end thereof are rollers or wheels 18 which run in the same guideways as the above-mentioned rollers or wheels 14. The rearward end position of the rollers 18 is shown in FIGURE 2, whereas in FIGURE 3 the carriage is shown in an intermediate position. The forward end of the carriage likewise carries rollers or wheels 19 which run on the reinforced underside 20 of the extension arm 9, the rollers 19 being held in position from above by a vertical plate 19a fixed to the carriage. The vertical plate extends through a slot in a horizontal guideway 21 in the extension arm and carries a shaft for the pair of rollers 19. The piston rod 22 of the ram cylinder 16 is attached to the rear of the jib, for instance by means of a strap 23, whereas an oppositely-extendible piston rod in the ram cylinder'17 is attached to a wall 24 in the extension arm 9. At points 4a and 4b, steady or guide members on the extension arm slidably engage the inside of the main jib arm.

The extension arm 9 is thus guided by rollers or wheels 14, on the one hand, and rollers or wheels 19, on the 7 other. The carriage 15 for the ram cylinders is mounted inside the jib in such a way that the full extension of the extension arm 9 requires a displacement of the ram cylinders by only half that distance. The ram cylinders are arranged to be controllably operable in either direction by a suitable hydraulic control system.

FIGURE illustrates a more compact form of construction of main arm and extension arm. The upper part of the main arm 4 again contains ledges 30 for supporting pairs of rollers 31. Each pair of rollers is connected with the extension arm 9 by a flat strap-like carrier member. The rollers 31.v thus serve for the suspension and easy slidable displacement of the extension arm,

while it is guided inside the main arm by direct sliding contact with the main arm walls 32. As already described, the carriage 33 for the ram cylinders 16, 17 is movably mounted inside the extension arm 9. The carriage 33 carries a vertical plate 33a which supports a shaft for each pair of rollers 33. Since the displacement of the carriage 33 proceeds in the same way as described with reference to the embodiment shown in FIGURE 4 it is unnecessary to repeat these details again.

Thetelescopic arrangement of the extension arm in the constructions shown in the drawings permits loads to be 4. tracted beyond the free end of the main arm affords the important advantage of enabling the main arm, which can be readily made of rugged construction, to guide the extension arm very reliably and at the same time to hold it very steady when depositing heavy loads on the vehicle. Thus, the possibility of vibration is minimized. The jib can be readily constructed to handle with ease and accuracy heavy loads, for instance loads Weighing up to 2.5 tons, as may be desired in, for example, the artificial stone industry.

Preferably, so that a'ram cylinder as hereinbefore described can operate positively in both axial directions, the cylinder contains a double-acting piston. In such a ram cylinder the inlet and outlet ports may be provided with non-return valves which are adapted to open automatically when the one or the other of the dead-center positions is reached.

We claim:

1. A'jib comprising a hollow main arm of substantially rectangular cross-section, an extension arm telescopically arranged within the main arm, two ram cylinders disposed side by side in the main arm, two rams extend ing in opposite directions from said cylinders and connected one to the main arm and the other to the extension arm for extending and retracting the extension arm, and a carriage carrying said cylinders, which carriage is axially movable in the main arm.

2. A jib according to claim 1 wherein longitudinal guideways are provided inthe main arm and the extension arm and the carriage is provided with supporting members slidably engaging said guideways.

3. A jib according to claim 2 wherein the supporting members comprise rollers adjacent the ends of the carriage. I V

4. A jib comprising a hollow main arm of substantially rectangular cross-section, an extension arm of substantially rectangular cross-section telescopically arranged in the main arm, loading means depending from the outer end of the extension arm, the underside of the main arm having a longitudinal aperture opening through the free end of the main arm for passage of the loading means, longitudinal guideways in the main arm, supporting rollers on the extension arm engaging said guideways, two ram cylinders disposed side by side within the main arm, two rams extending from the ram cylinders in opposite directions and connected one to the main arm and the other to the extension arm for extending and retracting the extension arm, a carriage for said ram cylinders axially movable in the main arm, a guideway in the extension arm, rollers at one end of the carriage engaging the aforesaid guideways in the main arm and rollers at the other end of the carriage engaging the guideway in the extension arm.

References Cited by the Examiner UNITED STATES PATENTS 2,886,005 5/59 Bryan 212--5l5 X 3,003,746 10/61 Gridley 25493 3,044,635 7/62 Kirsten 2l255 FOREIGN PATENTS 1,122,682 1/62 Germany.

SAMUEL F. COLEMAN, Primary Examiner. 

1. A JIB COMPRISING A HOLLOW MAIN ARM OF SUBSTANTIALLY RECTANGULAR CROSS-SECTION, AN EXTENSION ARM TELESCOPICALLY ARRANGED WITHIN THE MAIN ARM, TWO RAM CYLINDERS DISPOSED SIDE BY SIDE IN THE MAIN ARM, TWO RAMS EXTENDING IN OPPOSITE DIRECTIONS FROM SAID CYLINDERS AND CONNECTED ONE TO THE MAIN ARM AND THE OTHER TO THE EXTENSION ARM FOR EXTENDING AND RETRACTING THE EXTENSION ARMS, 